Study On Test And Operation Mechanism Of The Watertight And Water Shut-off Grout In Fractured Rock Mass

Ground project enlarged and the water conservancy project prospered at present, grouting has been widely used at home and abroad. Grouting purposes most to reinforce the rocks which don't meet the requirement of the project into the high-qualitied rocks that meet the requirement so that it can make full usage of the resources. Due to grouting engineering belonging to hidden project, the development of it is un-mature so far and the cases of theory falling behind practice remains now and then during the process of applying grouting in practice. Study on grouting material and behavior of grout plays a significant role in the technology of grouting. Grouting can seal up to shut off water and reinforce stratum because the materials can change liquid phase into solid phase. The grouting effect relates to the behavior of grout after being injected into the fractured rock mass, which is significant to grouting engineering.Base on collecting the past data, indoor test and theoretic analysis and appliance in the scene of projection, the affecting factors of the grouting effect has been concluded and summarized inhere. Furthermore, the paper has done research on the compound watertight grout components, proportion, behavior, consolidation mechanism, antiseepage mechanism and infiltration mechanism, and discusses the application in the project of fractured rock mass.For watertight and water shut-off grout in fractured rock mass, there is no matter that which material is used. The uppermost influential factor is the property of the material, the engineering mechanical property, design parameter for grouting and grouting technology.Through the laboratory test, it confirms preliminarily that the watertight and water shut-off grout in fractured rock mass is made up with clay, cement, water glass, NH₄H₂PO₄, water, etc.. The proportioning has a general best range through experiments, however, when applying it in the specified projection, the grout should be according to the practical case at spot as well as the practical experiment, so as to ensure the best formulation. The property of grout test has manifested that grout has excellent stability, controllability condition, grout-ability and the stone body formed after the grout has infused into the terrane has showed good effect and permanence, and the property of grout relates to the content of the components of it.The paper has maked further research on the process of consolidation of the grout by some test methods like SEM and found that the process is a series of physical chemical reaction among each component, which includes prehydration reaction of cement, prehydration of clay, inhibitory activate from NH₄H₂PO₄ to prehydration of cement, the reaction between cement hydrate and clay particle, the reaction between cement and water glass and the reaction between clay and water glass. The thermomechanical analysis for the process of consolidation shows that crystal and colloid created in the reaction is kainotyping and growing. Its propulsion can be described by free energy difference. And the analysis manifests that the reaction carrying-coefficient(a_b) has the trend to increase, which shows the reaction has autonomy.The forming process of the grout structure is different from the cement slurry's. In accordance to structural feature of it's plastic strength curve, the forming process of the grout structure can be divided into liquid state, gel state and solid state. And the grout can seal up and shut off water in the process. But there are big differences in the mode and the capability. The stone body is divided into three zones in grouting hole along the crack direction. They are consolidation zone, stability zone and porosity zone. And the three zones can interconvert in company with the grouting time in the grouting process.Grouting is adapted in fractured rock mass to seal up and shut off water, and the grout can do work because of the contrary resist function to direction of groundwater flowing. That is reverse process of water flow. If the grout material is considered as Newtonian fluid like water, the process of grouting moving is coherent with seepage in crack essentially. And the material flowing should accord with the relative hydraulics formula. Based on some hydraulics formula deduced by scholar at home and abroad, the thesis deduces and establishes the infiltrating model of grout in the plane and declining crack after considering that the grout is belong to Bingham fluid and has stream nucleus when it flows.The applied research of projection has manifested that the technics of grouting in fractured rock mass with grout is similar to others. But the grout is adapted the method of third class stirring and the method of major cycle in grouting. The injection rate and formulation should be controlled and adjusted in accordance with practical situation to obtain the optimal effect.